ITS#4643 getpass()

Since getpass() has been dropped from POSIX and is now considered unsafe, I've
decided to remove all detection of it. I've reworked the implementation of
lutil_getpass() which is used instead, when getpassphrase() is not present. In
addition to streamlining the code, I've removed the Merit-specific use of
telnet control codes, since that was specifically for a long obsolete
deployment at UMich (most likely the old ud client which was deleted from the
OpenLDAP tree years ago).
--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/